Web material such as paper, fabric, plastic film, metal foil, etc., is commonly wound onto a core. For example, paper rolls, such as newsprint or soft nip calendered rolls, are produced by winding a paper web onto a fiber core. Newsprint roll core diameters can vary, but two are prevalent, namely (nominal) 3-inch and (nominal) 6-inch inside diameter cores. Press room reel stands are equipped with core chucks sized to fit either 3-inch or 6-inch diameter cores, but not always both. Consequently, paper mills commonly supply newsprint wound on cores sized to fit each customer's unique combination of reel stands. For example, a customer having some reel stands equipped only with 3-inch core chucks and some reel stands equipped only with 6-inch core chucks will order some rolls wound on 3-inch cores and some rolls wound on 6-inch cores. This complicates management of press room roll inventories and restricts flexible allocation of rolls to reel stands, since rolls wound on 6-inch cores cannot be mounted on reel stands equipped only with 3-inch core chucks, and rolls wound on 3-inch cores cannot be mounted on reel stands equipped only with 6-inch core chucks.
Management of paper mill roll inventories is also complex. For example, a paper mill may need to delay production, until receipt of an appropriate combination of customer orders for rolls wound on 3-inch and 6-inch cores, to match the width of the paper machine winder for efficient production of the ordered rolls. This is because most winders cannot simultaneously wind sets of rolls on different diameter cores.
Prior art 6-to-3 inch core adapters have been used in an attempt to circumvent the foregoing problems. If such adapters are fitted into each of the opposed ends of a 6-inch diameter core, a paper roll wound on that core can be mounted on a reel stand equipped only with 3-inch core chucks. This allows a paper mill to efficiently wind all rolls onto 6-inch diameter cores—customers having reel stands equipped only with 3-inch core chucks can use such adapters to mount the rolls on those reel stands. This significantly improves press room efficiency—any warehoused roll of paper can be mounted on any reel stand at any time. Moreover, larger diameter cores are preferable because they are stiffer and less susceptible to vibration as the roll unwinds, which allows higher sustained operating speeds and improved runnability in the press room. Paper mills also benefit because excess production rolls wound on 6-inch diameter cores can be sold to customers who only have reel stands equipped with 3-inch core chucks, thus helping reduce the volume of dead stock in paper mill warehouses and avoiding expensive rewinding of paper rolls from cores of one diameter onto different diameter cores.
A typical prior art adapter is formed as a cylindrical steel sleeve, with an inside diameter suitable for engaging 3-inch core chucks. A plurality of ribs extend radially from the sleeve. The ribs are sized to tightly engage the inside diameter of a 6-inch diameter paper roll core, when the adapter's ribbed end is driven into the core. Such adapters usually have a protruding end flange which extends parallel to the side of the paper roll when the adapter is driven into the core. The flange necessitates reduction of the roll's width, which is undesirable because reduced-width rolls do not fully utilize the reel stand's width capacity. The protruding flange also precludes safe stacking, on end, of rolls in which such adapters have been installed. Such prior art adapters are also heavy, unwieldily, and may not effectively engage the core chuck's fingers, potentially allowing the roll to slip on the reel stand. Furthermore, installation of such prior art core adapters in a typical press room can be laborious and time consuming.
This invention addresses the shortcomings of such prior art adapters.